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Cost-Based Optimization of Service Compositions
, 1841
"... For providers of composite services preventing cases of SLA violations is crucial. Previous work has established runtime adaptation of compositions as a promising tool to achieve SLA conformance. However, in order to get a realistic and complete view of the decision process of service providers, the ..."
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Cited by 21 (14 self)
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For providers of composite services preventing cases of SLA violations is crucial. Previous work has established runtime adaptation of compositions as a promising tool to achieve SLA conformance. However, in order to get a realistic and complete view of the decision process of service providers, the costs of adaptation need to be taken into account. In this paper we formalize the problem of finding the optimal set of adaptations, which minimizes the total costs arising from SLA violations and the adaptations to prevent them. We present possible algorithms to solve this complex optimization problem, and detail an end-to-end system based on our earlier work on the PREvent (prediction and prevention based on event monitoring) framework, which clearly indicates the usefulness of our model. We discuss experimental results that show how the application of our approach leads to reduced costs for the service provider, and explain the circumstances in which different algorithms lead to more or less satisfactory results.
Automatic dynamic web service composition: A survey and problem formalization
- Comput. and Inf
, 2011
"... Abstract. The aim of Web service composition is to arrange multiple services into workflows supplying complex user needs. Due to the huge amount of Web services and the need to supply dynamically varying user goals, it is necessary to perform the composition automatically. The objective of this arti ..."
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Cited by 6 (0 self)
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Abstract. The aim of Web service composition is to arrange multiple services into workflows supplying complex user needs. Due to the huge amount of Web services and the need to supply dynamically varying user goals, it is necessary to perform the composition automatically. The objective of this article is to overview the issues of automatic dynamic Web service composition. We discuss the issues related to the semantics of services, which is important for automatic Web service composition. We propose a problem formalization contributing to the formal definition of the pre-/post-conditions, with possible value restrictions, and their relation to the semantics of services. We also provide an overview of several existing approaches dealing with the problem of Web service composition and discuss the current achievements in the field and depict some open research areas.
Effective automatic dynamic semantic web service composition,” Inf
- Sci. and Technol. Bulletin ACM Slovakia
, 2011
"... Web services are a popular technology used when diverse software system integration is in demand. The ability to make some functionality available through the Web has inspiring consequences. One of the intensively researched areas is the study how Web services can be used to dynamically create a fun ..."
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Web services are a popular technology used when diverse software system integration is in demand. The ability to make some functionality available through the Web has inspiring consequences. One of the intensively researched areas is the study how Web services can be used to dynamically create a functionality, based on the actual requirements. The basic idea is that multiple Web services can be combined together to form a composite service supplying more complex needs. The composition is realized automatically, on the fly, based on the actual goal. To facilitate this kind of Web service utilization, additional metadata depicting the functionality of single services is required. These metadata are provided in a form of semantic annotations. Our work deals with selected subproblems of the automatic dynamic semantic Web service composition. The sub-problems include the proper description of the behavior of Web services, management of the changes in the service environment, and handling multiple composition requests arriving continuously.
Optimized Execution of Business Processes on Crowdsourcing Platforms
"... Abstract—Crowdsourcing in enterprises is a promising approach for organizing a flexible workforce. Recent developments show that the idea gains additional momentum. However, an obstacle for widespread adoption is the lack of an integrated way to execute business processes based on a crowdsourcing pl ..."
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Abstract—Crowdsourcing in enterprises is a promising approach for organizing a flexible workforce. Recent developments show that the idea gains additional momentum. However, an obstacle for widespread adoption is the lack of an integrated way to execute business processes based on a crowdsourcing platform. The main difference compared to traditional approaches in business process execution is that tasks or activities cannot be directly assigned but are posted to the crowdsourcing platform, while people can choose deliberately which tasks to book and work on. In this paper we propose a framework for adaptive execution of business processes on top of a crowdsourcing platform. Based on historical data gathered by the platform we mine the booking behavior of people based on the nature and incentive of the crowdsourced tasks. Using the learned behavior model we derive an incentive management approach based on mathematical optimization that executes business processes in a cost-optimal way considering their deadlines. We evaluate our approach through simulations to prove the feasibility and effectiveness. The experiments verify our assumptions regarding the necessary ingredients of the approach and show the advantage of taking the booking behavior into account compared to the case when it is partially of fully neglected. I.
Efficiently Approximating the QoS of Composite Services in Mobile Ad-Hoc Networks
"... Infrastructure-less mobile ad-hoc networks enable the devel-opment of collaborative pervasive applications. Within such self-configurable networks, collaboration between devices is promoted by service-orientation by abstracting devices ’ re-sources as software services. QoS-aware service composi-tio ..."
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Infrastructure-less mobile ad-hoc networks enable the devel-opment of collaborative pervasive applications. Within such self-configurable networks, collaboration between devices is promoted by service-orientation by abstracting devices ’ re-sources as software services. QoS-aware service composi-tion concerns the realisation of complex service collabora-tions and functionalities while meeting QoS goals. However, the unpredictably changing topologies and resources avail-ability in such environments, make QoS-aware composition challenging. Moreover, when composing services offered by diverse devices, there is no trivial relationship between the QoS of the composite service and its component services. In this paper, we present a performance prediction approach for efficiently approximating the QoS of composite services in the context of dynamic service-based mobile ad-hoc net-works. First, we identify general prediction variables useful for predicting the quality of composite applications formed over multi-hop ad-hoc networks. Based on these variables, we develop and evaluate a range of prediction models for response time, network latency, success ratio and overall energy consumption. Our experimental results show that simple models constructed from combinations of the iden-tified predictor variables can approximate the quality of a service composition accurately enough and with little com-putational effort. Our approach is evaluated in the context of a simulated fire-fighting pervasive application. 1.
A Framework for Adapting Service-oriented Applications based on Functional/Extra-functional Requirements Tradeoffs
"... Abstract—This paper introduces an adaptation framework for service-oriented applications based on trade-offs between functional and extra-functional (e.g., availability, performance, and adaptation cost) requirements. The framework relies on an optimization method for adaptation space exploration ba ..."
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Abstract—This paper introduces an adaptation framework for service-oriented applications based on trade-offs between functional and extra-functional (e.g., availability, performance, and adaptation cost) requirements. The framework relies on an optimization method for adaptation space exploration based on the combined use of meta-heuristic search techniques and of functional and extra-functional patterns (e.g., architectural design patterns and tactics). A formal service-oriented compo-nent model, called SCA-ASM, is also adopted for the specifi-cation and functional analysis of service-oriented applications. Through a sample application, we exemplify the methodology with emphasis on the use of extra-functional patterns. Keywords-Service-oriented applications; software adaptation and evolution; extra-functional adaptation patterns. I.
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"... Effective QoS aware service composition based on forward chaining with service space restriction ..."
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Effective QoS aware service composition based on forward chaining with service space restriction
Surrogate-Assisted Optimisation of Composite Applications in Mobile Ad-hoc Networks
"... Infrastructure-less mobile ad-hoc networks enable the de-velopment of collaborative pervasive applications. Within such dynamic networks, collaboration between devices can be realised through service-orientation by abstracting device resources as services. Recently, a framework for QoS-aware service ..."
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Infrastructure-less mobile ad-hoc networks enable the de-velopment of collaborative pervasive applications. Within such dynamic networks, collaboration between devices can be realised through service-orientation by abstracting device resources as services. Recently, a framework for QoS-aware service composition has been introduced which takes into account a spectrum of orchestration patterns, and enables compositions of a better QoS than traditional centralised orchestration approaches. In this paper, we focus on the automated exploration of trade-off compositions within the search space defined by this flexible composition model. For the studied problem, the evaluation of the fitness functions guiding the search process is computationally expensive be-cause it either involves a high-fidelity simulation or actu-ally requires calling the composite service. To overcome this limitation, we have developed efficient surrogate models for estimating the QoS metrics of a candidate solution during the search. Our experimental results show that the use of surrogates can produce solutions with good convergence and diversity properties at a much lower computational effort.
Dynamic Service Composition Using Core Service Identification
"... Service selection and binding for building composite services is a critical but difficult to resolve issue in the domain of service-oriented computing. This paper proposes an innovative approach to address this issue, in which every abstract component service in the composition is assigned a weight ..."
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Service selection and binding for building composite services is a critical but difficult to resolve issue in the domain of service-oriented computing. This paper proposes an innovative approach to address this issue, in which every abstract component service in the composition is assigned a weight value to represent its importance according to designer scoring and basis path analysis, thereby generating a weighted service flow. Composite services, including selected concrete component services, are produced according to the weighted service flow and genetic algorithms. The generated composite service ensures acceptable quality and guarantees the core component ser-vices, which are most likely to influence the overall service flow, are more robust than the others. Besides, a novel fault handling method based on the identified core services is proposed to enhance the availability of compos-ite services. Experimental results demonstrate the proposed approach can effectively maintain the quality of core component services.
